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List of Chemical Substances
Published in T.S.S. Dikshith, and Safety, 2016
Students and occupational workers should be careful during use and handling of diphe-nylamine. Workers should wear impervious protective clothing, including boots, gloves, a laboratory coat, apron or coveralls, as appropriate, to prevent skin contact. Finely dispersed particles of diphenylamine form explosive mixtures in air. Diphenylamine is very harmful on exposures by swallowing, inhalation, and/or skin absorption. Diphenylamine causes irritation to the skin, eyes, and respiratory tract, and causes blood vascular changes leading to methemoglobinemia.
Antioxidants
Published in Leslie R. Rudnick, Lubricant Additives, 2017
Robert G. Rowland, Jun Dong, Cyril A. Migdal
Figure 1.3 illustrates a commercial route to the preparation of diphenylamine and the typical synthetic routes to some commonly used alkylated diphenylamines. The diphenylamine synthesis reactions start with benzene, which is first converted to nitrobenzene [79], followed by a high-temperature reduction to aniline [80]. Under very high-temperature (400°C–500°C) and high-pressure (50–150 psi) conditions, aniline can undergo a catalytic vapor-phase conversion to form diphenylamine [81].
Direct production of polyhydroxybutyrate from waste starch by newly-isolated Bacillus aryabhattai T34-N4
Published in Environmental Technology, 2020
Wichittra Bomrungnok, Takamitsu Arai, Tadashi Yoshihashi, Kumar Sudesh, Tamao Hatta, Akihiko Kosugi
The amount of PHB was assayed by production of crotonic acid [19]. PHB was analysed as crotonic acid on an Aminex HPX-87H ion-exclusion organic-acid analysis column (Bio-Rad Laboratories, Richmond, CA, USA) with 0.014 M H2SO4 as the eluent and a flow rate of 0.6 mL/min at 50°C. Total starch was determined by the amyloglucosidase/α-amylase method (Megazyme, Wicklow, Ireland). Reducing sugar was determined by the modified Nelson-Somogyi method [19]. Thermal properties of PHB were determined by differential scanning calorimetry. Samples were measured between −30°C and 200°C at a heating rate of 10°C/min and a cooling rate of −10°C/min. Gel permeation chromatography was used to determine the weight-average molecular weight (Mw) and number-average molecular weight (Mn) of PHB. Samples were analysed on a Shodex GPC HFIP-G instrument connected to an HFIP-606M column with 5 mM sodium trifluoroacetate in hexafluoroisopropanol at a flow rate of 0.2 mL/min at 40°C. Starch hydrolysis products were analysed by thin-layer chromatography (TLC). A mixture of standard maltooligosaccharides (G1–G7) was used for reference. TLC of the hydrolysis products was performed on DC-Fertigplatten SIL G-25 plates (Macherey-Nagel, Oensingen, Switzerland) developed with 85:15 (v/v) 1-propanol:water as solvent. Hydrolysis products were visualised by spraying plates with aniline-diphenylamine reagent.
Combined use of polymeric ferric sulfate and chitosan as a conditioning aid for enhanced digested sludge dewatering
Published in Environmental Technology, 2019
Jing Wang, Kangmin Chon, Xianghao Ren, Haizhong Wu, Yingying Kou, Moon-Hyun Hwang, Kyu-Jung Chae
The turbidity of the sludge supernatant was measured using a turbidimeter (2100Q, Hach, Loveland, CO, USA). The concentrations of proteins, polysaccharides, and deoxyribonucleic acids (DNAs) in the sludge supernatant (volume of each sample = 10 mL) were measured using the Folin-Lowry, anthrone-sulfuric acid, and diphenylamine methods, respectively [26,27]. The calorific values of the dried sludge samples were calculated using an empirical equation [high heating value (HHV; kJ/kg) = 25,368 × the ratio of volatile solids to total solids (VS/TS) − 1918.8] suggested by Shizas and Bagley [28]. The changes in the morphological features of the sludge flocs were identified using scanning electron microscopy (SEM; Quanta200 FEG, FEI, Eindhoven, Netherlands). Concentrations of soluble chemical oxygen demand (SCOD) and TP in the supernatant of the digested sludge were measured using the dichromic acid (GB11914-89) and ammonium molybdate (GB11893-89) methods, respectively [29].
An overview of simultaneous saccharification and fermentation of starchy and lignocellulosic biomass for bio-ethanol production
Published in Biofuels, 2019
The concentration of ethanol in a sample can also be determined by the titration method and the spectrophotometric method. In the titration based method, acidified potassium dichromate can be used. The method is based on reacting the sample with an excess of potassium dichromate; all ethanol will be oxidized to acetic acid. The excess dichromate is determined by titration against sodium thiosulfate. Subtracting the amount of excess dichromate from the initial amount gives the amount of ethanol present. Accuracy can be improved by calibrating the dichromate solution against a blank. In this process, potassium dichromate, ferrous ammonium sulfate and diphenylamine solutions can be used as the reagent for estimation of ethanol concentration. The fermented sample will diluted 10 times with distilled water. The diluted sample is distilled against K2Cr2O7 (10 ml) containing concentrated H2SO4 (5–6 ml). The distilled sample can be titrated against freshly prepared ferrous ammonium sulfate solution with diphenylamine as an indicator. The appearance of a green color indicates the end point of the titration. The burette reading (amount ferrous ammonium sulfate) is recorded to calculate the amount (in percentage) of ethanol present in the sample [80].